Inheriting Y-DNA haplotypes

[diskov]

If I am to understand Y chromosome haplotypes correctly:

Let's say that I am male. I have an X chromosome from my mother and a Y chromosome from my father. Because the Y chromosome is passed directly through my father's paternal line, does that mean I have more in common genetically with my great-great-great-great grandfather on my father's side (in the paternal line) than I do with any great-great-great-great grandfather/grandmother on any other line of my mother's or my father's?non-paternal line? I am assuming that I have 50% of the same DNA as every ancestor in my father's line because we all inherited the same Y-Chromosome since the Y DNA haplotype was created.

Also, my grandfather had his DNA tested recently. Is there any chance that I can have slightly different STR markers that change my Y-DNA haplotype? after two generations?

Thanks.

[Babybel56]

In terms of genetic information the y-chromosome is almost vestigial and contains little coding information at all. All of the other chromosomes aren't conserved like this (so you're 50% statement is flawed) and for each generation there will be new combinations from both of the parents rather than them all coming from the paternal line.
So in terms of total genetic material (and this is all just based on probability) you probably share more with your mother than your father, but as far back as great-great-great-great grandfathers/mothers you could be correct because there's a chance that she had no chromosomes in common with you, whereas he must have at least had the y.

Hope this helps!

[JackBean]

my grandfather had his DNA tested recently. Is there any chance that I can have slightly different STR markers that change my Y-DNA haplotype? after two generations?

Sure. The mutations must occur somewhere I've been on some presentation just last Friday and they were speaking also about Y chromosomes and the guy said, that they have really noticed some change in father/son's Y chromosomes